1. Technical Field
The invention relates generally to a ring assembly for a surface drain which prevents liquid flowing over the surface from entering the drain. In particular, the invention relates to a drain ring assembly for preventing aviation fuel spilled on a concrete apron during a aircraft fueling operation from entering a drain of a surface water drainage system for the concrete apron.
2. Background Art
At many airports, both military and commercial, aircraft fueling operations are performed on a concrete apron which slopes gradually to a number of storm drains of various shapes and sizes. In the past, whenever fuel is spilled onto the apron in sufficient quantity that the fuel will reach nearby storm drains, various covers or drop mats were placed over these nearby drains in an effort to prevent fuel from entering state waters. Industry drop mats suitable for storm drains are relatively expensive, generally several hundred dollars, and can only be used a few times. Also, these drop mats are generally too heavy to be carried about and installed by a single person. Further, when such drop mats are used during a fuel spill, there is no way of determining if any of the fuel got into any of the drains, and thus it was necessary to report many spills to the state as a possible violation of state and/or federal environmental regulations regarding pollution of state waters.